<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div{
            color: red;
        }
        p{
            color: blue !important;/*重要的*/
        }
        #p2{
            color: green
        }
    </style>
</head>
<body>
<p>p1</p>
<div>
  <p id="p2">p2</p>
  <span>span1</span>
  <a href="">超链接</a>
</div>
</body>
</html>